1. Field
Apparatuses and methods consistent with exemplary embodiments relate to optical modulators, and more particularly, to a transmission type high-absorption optical modulator and a method of manufacturing the same.
2. Description of the Related Art
Three-dimensional (3D) photography and 3D displays have become very popular issues in the display industry and the application of these technologies has extended to sensors and game machines.
Unlike a stereo type 3D image representation method, data for 3D image representation using depth information also includes distance information and thus may be used not only for 3D displays but also for precision measurement devices or sensors.
A 3D depth sensor using an infrared (IR) light source adjusts IR transmittance by changing the voltage of a transmission type optical modulator and senses depth based on a change in light transmittance. A variation is generated in the absorption ratio of a transmission type optical modulator based on whether the voltage is on or off (Von/Voff), and a shutter for the IR light source may be opened or closed based on the variation. An optical modulator in a 3D camera is referred to as an optical shutter. A depth image may be obtained by using a CMOS image sensor (CIS) with an IR optical signal that is modulated by using an optical modulator operating at an alternating current (AC) of 20 MHz.
An optical modulator may be used as an image type distance sensor that captures an image of an object like a photographic image in order to provide distance data for every part of a screen. An optical modulator may be used in devices in a variety of fields. For example, an optical modulator may be used in precision measurement equipment, sensors for safety or convenience inside and outside vehicles, camera auto-focusing, sensors for closed circuit TVs (CCTVs) for crime prevention, 3D object surface printing, 3D broadcasting cameras, 3D endoscope cameras, distance sensors for improving the accuracy of military missiles, etc. The possible applications of optical modulators range from daily use purposes to military purposes.